%set up the model (global variables)

global  time dt
global  line_length depth
global  sources receivers spacing
global  velocity1 layer 
global  tref wref

dt = 2;          % time sampling interval
time = 0:dt:800;  % time sampling
amplitude = 50;

receivers = 0:25:1000;    % positions of 41 receivers
depth = 500;

line_length = receivers(end);                 % total length of seismic line
spacing = line_length/(length(receivers)-1);  % receiver spacing

% draw and pick a reflecting layer
layer1 = picklayer(line_length,depth);
layer2 = picklayer(line_length,depth);
layer3 = picklayer(line_length,depth);
save model1.mat layer*   section